But if Leiweke, president of TFC owners Maple Leaf Sports and Entertainment (MLSE), and all those involved in the reported $100 million deal were really preparing for economic hara-kiri they were doing it with a smile on their faces.
There were no frowns anywhere as MLSE, whose sporting portfolio also includes the NHL's Toronto Maple Leafs and NBA's Raptors, introduced Defoe and Bradley during a splashy unveiling at a popular upscale sports bar.
Defoe, who joined from Tottenham Hotspur where he was the Premier League club's fifth highest scorer with 142 goals and Bradley, a hard-nosed midfielder lured from Serie A giants AS Roma, joined Brazilian striker Gilberto to cap an off-season shopping spree never before seen in Major League Soccer.
"To do one DP (designated player) is a smart move, to do two DP's is not the smartest thing ever done and to do three is financial suicide," Leiweke told a news conference on Monday.
"We don't have enough seats to make economic sense out of this and we have raised our ticket prices.
"But we needed to repair the integrity of the relationship with our fans and to the owners credit they understand the first year is a lost leader and we're not going to dwell on that."
While Leiweke, the man who brokered the deals that brought David Beckham and Robbie Keane to the Los Angeles Galaxy, conceded the signings made no financial sense he said it was an opportunity too good to pass up as MLSE tries to breathe new life into a club which has failed miserably on the pitch.
When TFC entered the league seven years ago to great fanfare and wild support, they were held up as the prototype MLS franchise and the template of how to get a club off the ground.
But in seven years they have yet to reach the playoffs and last season won just six games on the way to finishing bottom of the table in 2012 with just five victories.
With the franchise in disarray and the fan base shrinking, MLSE's hand was forced into making a big move to get back on track.
"You do it because you can and we have the owners who are committed and they understand it's going to take a year two to get this to a point where it makes financial sense," Leiweke said.
"Obviously we know that in this marketplace we have a chance to take soccer to the next level.
"The chance to clean the slate, start fresh, go back to creating the environment like it was at the beginning and doing it with two guys like this we could not pass up that opportunity."
A red double decker bus with "It's a Bloody Big Deal" painted across its side was parked outside the news conference and for Major League Soccer there have been few more significant signings.
Beckham, Keane and French international Thierry Henry all came to the MLS late in their careers but MLSE displayed unusual aggression by landing two high-profile players in their prime.
Defoe's deal is believed to be for four years at $8 million a season while Bradley signed on for six years and $36 million. Both contracts are also believed to contain marketing incentives. Leiweke confirmed that MLSE paid MLS record transfer fees of close to $10 million for each player.
Bold moves indeed in a league that operates under a tight $3 million salary cap but allows each team up to three designated players that do not count against the cap.
"Leave no doubt these are record transfer fees but they are not record transfer fees when you look at the world market and we decided to go swim in the world market," Leiweke said.
"We were swimming in a pond with the Bundesliga, Serie A, EPL and when you look at those leagues these are not extraordinary transfer fees for either of these guys."
The view of the signings from the other side of the Atlantic were not as upbeat, the English press slamming Defoe's decision as a dead-end move going from one of the soccer's iconic clubs in the world's most popular league to the worst team in a mediocre league.
Defoe, dressed in a sharp dark suit and tie sat smiling alongside Bradley, who dressed down for the occasion in jeans, trainers and open black shirt and talked altruistically of helping young players grow the sport in North America.
But ultimately the huge financial gamble will be judged on wins, losses and trophies.
"We didn't accomplish anything today we created a very good opportunity but the hard work is in front of us," cautioned Leiweke. "Nothing is won today.
"A lot of people don't see the vision we do and now what we have to do is prove them wrong."